Re: [PATCH bpf-next 0/5] libbpf: error reporting changes for v1.0

From: Andrii Nakryiko <andrii.nakryiko@gmail.com>
To: "Toke Høiland-Jørgensen" <toke@redhat.com>
Cc: John Fastabend <john.fastabend@gmail.com>,
	Stanislav Fomichev <sdf@google.com>,
	Andrii Nakryiko <andrii@kernel.org>, bpf <bpf@vger.kernel.org>,
	Networking <netdev@vger.kernel.org>,
	Alexei Starovoitov <ast@fb.com>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Kernel Team <kernel-team@fb.com>
Subject: Re: [PATCH bpf-next 0/5] libbpf: error reporting changes for v1.0
Date: Mon, 24 May 2021 14:26:19 -0700	[thread overview]
Message-ID: <CAEf4BzadPCOboLov7dbVAQAcQtNj+x4CP7pKutXxo90q7oUuLQ@mail.gmail.com> (raw)
In-Reply-To: <87a6ojzwdi.fsf@toke.dk>

On Mon, May 24, 2021 at 1:53 PM Toke Høiland-Jørgensen <toke@redhat.com> wrote:
>
> Andrii Nakryiko <andrii.nakryiko@gmail.com> writes:
>
> > On Sun, May 23, 2021 at 11:36 PM John Fastabend
> > <john.fastabend@gmail.com> wrote:
> >>
> >> Andrii Nakryiko wrote:
> >> > Implement error reporting changes discussed in "Libbpf: the road to v1.0"
> >> > ([0]) document.
> >> >
> >> > Libbpf gets a new API, libbpf_set_strict_mode() which accepts a set of flags
> >> > that turn on a set of libbpf 1.0 changes, that might be potentially breaking.
> >> > It's possible to opt-in into all current and future 1.0 features by specifying
> >> > LIBBPF_STRICT_ALL flag.
> >> >
> >> > When some of the 1.0 "features" are requested, libbpf APIs might behave
> >> > differently. In this patch set a first set of changes are implemented, all
> >> > related to the way libbpf returns errors. See individual patches for details.
> >> >
> >> > Patch #1 adds a no-op libbpf_set_strict_mode() functionality to enable
> >> > updating selftests.
> >> >
> >> > Patch #2 gets rid of all the bad code patterns that will break in libbpf 1.0
> >> > (exact -1 comparison for low-level APIs, direct IS_ERR() macro usage to check
> >> > pointer-returning APIs for error, etc). These changes make selftest work in
> >> > both legacy and 1.0 libbpf modes. Selftests also opt-in into 100% libbpf 1.0
> >> > mode to automatically gain all the subsequent changes, which will come in
> >> > follow up patches.
> >> >
> >> > Patch #3 streamlines error reporting for low-level APIs wrapping bpf() syscall.
> >> >
> >> > Patch #4 streamlines errors for all the rest APIs.
> >> >
> >> > Patch #5 ensures that BPF skeletons propagate errors properly as well, as
> >> > currently on error some APIs will return NULL with no way of checking exact
> >> > error code.
> >> >
> >> >   [0] https://docs.google.com/document/d/1UyjTZuPFWiPFyKk1tV5an11_iaRuec6U-ZESZ54nNTY
> >> >
> >> > Andrii Nakryiko (5):
> >> >   libbpf: add libbpf_set_strict_mode() API to turn on libbpf 1.0
> >> >     behaviors
> >> >   selftests/bpf: turn on libbpf 1.0 mode and fix all IS_ERR checks
> >> >   libbpf: streamline error reporting for low-level APIs
> >> >   libbpf: streamline error reporting for high-level APIs
> >> >   bpftool: set errno on skeleton failures and propagate errors
> >> >
> >>
> >> LGTM for the series,
> >>
> >> Acked-by: John Fastabend <john.fastabend@gmail.com>
> >
> > Thanks, John!
> >
> > Toke, Stanislav, you cared about these aspects of libbpf 1.0 (by
> > commenting on the doc itself), do you mind also taking a brief look
> > and letting me know if this works for your use cases? Thanks!
>
> Changes LGTM:
>
> Acked-by: Toke Høiland-Jørgensen <toke@redhat.com>
>
> As a side note, the series seems to have been chopped up into individual
> emails with no threading; was a bit weird that I had to go hunting for
> the individual patches in my mailbox...
>

That's my bad, I messed up and sent them individually and probably
that's why they weren't threaded properly.